Artificial tooth-crown



(No Model.)

J. E. LOW.

ARTIFICIAL TOOTH GROWN.

I Patented'Jan. 17, 1888.

Inventori- JZzmz-s Z. Iow,

N. PETERS. PhMO-UXMIHOHBII Walhinzion. D.C.

UNrTED STATES PATENT OF ICE.

JAMES E. LOW, OF CHICAGO, ILLINOIS.

ARTIFICIAL TOOTH-CROWN.

SPECIFICATION forming part'of Letters Patent No. 376,603, dated January17, 1888. Application filed February 12, 1885. Renewed April 15, 1887.Serial No. 234,932. (No model.)

.To' all whom it may concern.-

Be it knownthat I. JAMES E. LOW, of Chicago, in the county of Cook andState of Illinois, have invented certain new and useful Improvements inArtificial Tooth-Crowns; and I do hereby declare that the following is afull, clear, and exact description thereof, reference being had to theaccompanying drawings, and to the letters of reference marked thereon,which form a part of this specification.

The object of this invention is to provide an improvedconstruction inartificial toothcrowns and in means for attaching such crowns to orsupporting them upon stumps or roots of natural teeth; and it consistsin the matters 137,831, for an improvement in artificial dentures, filedby me July 16, 188i, and is claimed herein only as applied in theconstruction of artificial crowns. The use of the form of crown hereinshown'is especially advantageous, in connection with the device hereinshown, for attaching crowns to natural roots, as will hereinafterappear, and the said crown is therefore claimed herein also inconnnection with the said attaching device.

As it relates to means for attaching artificial crowns to natural roots,the invention consists, generally, in the combination, with anartificial crown, of a metal plug or plugs fitted to a socket or socketsin the root and secured in said socket or socketsby cement and solderedto a metal partof the crown, it usually being preferred to provide aplug for each prong of the root when the latter has two or more prongs.In carrying out this part of the invention the plug is made larger atits upper or outer thanat its inner or lower end, and is also stepped orshouldered at its sides, whereby the plug is made more rigid at itsouter end, a broad surface is afforded at such with two plugs.

outer end for the attachmentof the crown, and a relatively large area ofcemented surfaces for uniting the plug and tooth is afforded. Inconnection with the plug or plugs a metal cap is preferably used, saidcap being attached to the plug and fitted over the upper end of theroot. As shown in the accompanying drawings, the cap is made separatefrom the plug andsecured to the latter and to the artificial crown bysolder, and both the cap and the plug secured to the tooth by cement.The said cap, when made separate from the plug, is desirably but notnecessarily provided with an aperture or apertures corresponding inposition with the plug or plugs, the object of said aperture orapertures being to enable the cap, plug or plugs, and crown to besecured together at one soldering, as will hereinafter appear.

The invention may be more fully understood by reference to theaccompanying drawings, in which- Figure l is a perspective view of theartificial crown applied to a stump or root. Fig. 2 is a verticalsection thereof. spective view of the rear side of a metallic base orsocket for the porcelain body or veneer of the artificial crown. Fig. 4is a perspective view of the front side of said base or socket. Fig. 5is a perspective view of the metal cap shown in Fig. 2. Fig. 6 is a perspeetive view of the metal plug. Fig. 7 is a transverse section of theporcelain body or veneer and the metal base or socket therefor, takenupon line 00 m ofFig. 2. Fig.8 is asectional'view of a two-pronged rootprovided Fig. 9 is a sectional view of the artificial crown shown inFig. 8, taken upon line a; x of said figure. Fig. 10 is aperspectiveview illustrating a thre'e-pronged root provided with three plugs and acap therefor. Fig. 11 is a sectional view of a root provided with a plugand cap, the plug having a projection fitting the aperture in the cap.

A refersto'the stump or root of a natural tooth, and B'indicatcs, as aWhole, an artificial crown, which is shown in the drawings as composedof a porcelain body or veneer, G, and a metal backing, base, or socket,D, to which the porcelain part is secured by cement, the said porcelainpart and metal backing being provided with interlocking recesses andFig. 3 is a persaid porcelain part 0.

projections, as c and d, which are accurately fitted to each other,whereby the said parts may be firmly secured together by cement.

E is a metal plug, which is accurately fitted in and secured by cementto the walls of a socket, a, bored or drilled in the stump or root, andF is a metal cap which is attached to the plug, and which issaucer-shaped or provided with a conical marginal part or flange made toconform accurately to the adjacent rounded or beveled end or top surfaceof the root. In the drawings the cap is shown as made separate from theplug and provided with an aperture which is located over the plug whenthe parts are in place, whereby the plug and the cap may be united tothe toothcrown by a body of solder passing through the said aperture, ashereinafter more fully set forth. Vhen the cap is thus made, it isfitted to the root after the plug has been fitted in thesocket of theroot, the said plug, for convenience in fitting the parts, usually beingcut or ground down at its top end fiush with the top of the root, whichlatter is likewise preferably cut or ground down level with the plug andbeveled about its margin.

The metal base D is, as shown in Figs. 1, 2, 3, 4, and 7, made of thinor sheet metal and is indented to form two oblong sockets, d, in whichcorrespondingly-shaped projections c on the rear side of the porcelainbody 0 are received, said base D preferably being provided with amarginal flange, d, which cartends over or embraces the side edges ofthe In the crown for the double or back tooth (shown in Fig. 8) thecrown is similarly composed of a porcelain part or veneer, G, and ametal socket, D, the latter being, as shown, preferably provided with apart or flange, (P, at the base of the crown, which forms a relativelylarge surface in contact with the cap F when the parts are securedtogether.

The socket a in the stump or root is made somewhat larger at its upperthan at its lower end, and has its diameter abruptly contracted atseveral points between its upper and lower ends, so as to form annularshoulders or steps a at intervals along its sides.

The metal plug is likewise made larger at its upper or outer than at itslower or inner end, and has its diameter abruptly contracted atintervals, so as to form annular shoulders e, corresponding in shape andposition with the steps in the socket, to which latter the plug is, inthese and all other respects, made to accurately conform. I

In the operation of fitting the plug to the root any suitable means maybe used for making the socket in the root, a drill or reamer adapted toform an aperture of the exact size and shape of the plug preferablybeing used for this purpose.

Theplug islarger,and consequently stronger or more rigid, at its upperor outer than at its lower or inner end, and a relatively large area ofmetal is at the same time afforded at the upper end for the attachmentof the cap F and other parts by solder. By this construction, also, theplug is better adapted to fill all roots, for the reason that the cavityof a decayed root is located at the upper or outer part of the root, andthe upper or larger part of the plug is adapted to fill such cavity. Ashouldered form of plug is also of advantage, inasmuch as the shoulderstend to prevent the moisture and acids of the mouth from enteringbetween the cement-ed surfaces of the plug and tooth, and therebydestroying the adhe sion of the cement.

The shouldered or stepped conformation of both the plug and the socketprovides, also, an extended bearing for the plugavhereby the union ofthe two by cement will be stronger and more durable, and the union orconnection of the plug with the stump or root readily attained after theplug with the artificial crown soldered thereto has been placed in thesocket.

An important advantage is obtained, also, by beveling the edge or cornerof the stump and fitting the marginal portion of the cap F to saidbeveled part of the teeth, as above described, for the reasons that thecrown is thereby additionally held from lateral movement, and that theliability of the entrance of moisture to'the joint between the plug androot is thereby much lessened. In the application of the plug and cap toa single root, as shown in Figs. 1 and 2, the upper end of the root maybe conveniently beveled bythe use of a concave reamer provided with acentral projection adapted to engage the plug-socket,\vl1ereby thereamer may be accurately centered and the beveled surface of the rootmade concentric with the said plug-socket. \Vhcn the beveled surface isformed in this manner, the inner surface of the flange of the cap Finayobviously be made to conform to the shape of the reamer, and said capmay thereby be fitted to the tooth with little difficulty. It isobvious, furthermore, that also the plug, instead of being ground downlevel with the root, may be provided upon its top surface with a centralprojection fitted to the aperture f in the cap F, as indicated at c,Fig. 11, whereby the plug and cap may be readily secured together in theproper relative position without the use of any special devices forholding them while being soldered. The use of such projection e is not,however, confined to a construction in which the root is provided with abeveled edge concentric with the plugsocket, for the reason that anapertured cap may be fitted to the projection upon the plug and theedges of said cap then made to conform to the margins of the top of theroot, either when said margins are irregularly beveled or unbeveled,withadvantages in the subsequent operation of attaching the crown, whichwill be hereinafter set forth.

In the use of the devices above described for securing a crown to atwo-pronged root, as shown in Fig. 8, a socket is formed in each ICOprong and two plugs are inserted. Inthis case the plugs will usually beground down flush with the top of the root and the cap F then fittedover the top of the plugs and the root, which latter will preferably bebeveled at its top edge, as above described. In this case the use ofplugs provided with projections e", fitted to the aperturesin the cap,will not usually be employed, for the reason that the distance betweenthe plugs will seldom, if ever, be the same, and the exact determinationof the distance apart of the apertures to correspond with the positionof theplugs may be found somewhat diffieult. The tooth-crown illustratedin Fig. 8, a section of which is shown in Fig. 9, is provided withinterlocking recesses and proj ections, and is generally similar to thecrowns shown in the prior application above referred to.

In Fig. 10 a three-pronged root is shown as fitted with three plugs andan apertu red cap, F, of a form adapted for application to said root.

One convenient way of applying the artificial crown to the stump or rootwill be to first properly cut or grind down the latter and then bore ordrill out the socket or sockets therein. The metal plug or plugs willnext be fitted in the socket or sockets, after which the metal cap Fwill be fitted upon the stump and the top of the plug or plugs therein.A cast or model will next be made ot" the stump or root,'the metal cap,and the adjacent portions of the jaw, and a reverse cast then made ofthe first cast or model, in which the metal cap and the plug or plugsremoved from the stump or root will be properly placed, whereby acorrect representation of the jaw with the base fitted o'n'a stump orroot in the jaw and the plug or plugs fitted in the stump or root isobtained. In the use of a plug with a flat top, or one which is grounddown flush with the top ofthe root, the plug and the cap, either whenthe latter is or is not provided with an aperture, f, will during thisoperation be held in proper relative position by the use of hard wax orby other meansrwell known to a person skilled in the art. \Vhen,l1owever,.the plug is provided witha pro- 5o jection, el fitted to anaperture,f, in the cap,

will flow between the surfaces of the said cap and the plug or plugs,and thereby enable the several parts to be firmly united by one body ofsolder and at one soldering. When a sheetmetal base, Dsuch as is shownin Figs. 1, 2, 3, and 4-is used, the solder will be so disposed as tofill the space between and around the projections formed by thedepressions d,

owed to the root by cement.

so that the body of solder will be flush with said projections, andthereby give a smooth and finished backing of solder in rear of themetal base.

, The important advantage obtained by the use of the crown composed of aporcelain and metal part united by cement in connection with the devicesfor securing the crown to the root is, that the porcelain body or veneerafter the crown has been properly arranged in position may be removedfrom the metal base while the several parts are being soldered together,and afterward secured permanently in place by cement;

I am aware that it has been proposed heretofore to secure a crowncomprising a metal base and a porcelain body secured together by theusual dowel-pins toa natural root by forming a cylindric or shoulderedprojection upon the upper or outer end of the root and fitting the saidprojection to asocket in the metal base of the crown, the crown beingsecured to the root by cement. This construction is objectionable forthe reason that it is not applicable to short roots,or to those whichare much decayed,or decayed principally in the middle, where a cavityusually forms, it being obvious that the central part of the tooth orroot must in such construction be depended upon principally to withstandlateral strain upon the crown. Such prior construct-ion, also, is notapplicable to back teeth, or those with more than one prong or root, forthe reason that sufficientsupport will not be afforded to the crown byone projection formed upon the root, and

it is seldom, if ever, practicable to form the two or more projectionsupon the same root.

I am also aware that artificiatcrowns have been supported by means ofcylindric plugs of metal provided with flanged caps and se- Such plugsfail to support the crowns on account of their lack of rigidity at theirupper ends and of the relatively small area of contact with the root toresist lateral strain and to afford a sufficiently strong union by theuse of cement. It is impracticable, also, to successfully employ plugsof this character when the tooth or root is much decayed in its top, forthe reason thatin such case the plug will not be sufficiently supportedby the root against lateral movement at its upper end, at which point itis obviously subjected to the greatest strain. In the use of a plugformed as herein proposed the latter may in all cases be fitted incontact with the outer part of the root at its upper end, such outerpart being the hardest and strongest part. of the root and that-which isthe least liable to be decayed, and the said plug is thereby madecapable of effectually resisting lateral strain,and means is at the sametime provided for firmly securing the plug in place by cement. y

In the use of small cylindric plugs with flanged'caps,furthermore, thecap has been made fiat with a cylindric flange, and the exteriorsubstance of the tooth cut away about IIO the top of the root to form agroove or rabbet to receive said flange. The cutting away of the toothsubstance to a cylindric form, as required by that form of cap, ishighly disadvantageous, inasmuch as the hardest and strongest part ofthe root is thereby removed and its capability of rigidly sustaining thecrown greatly diminished. In connection with the tapered plug made asherein described, therefore, I preferably employ a saucer-shaped orconical cap which is without any cylindric flange and fits by its underconcaved surface against the upper end of the root, which end is beveledor rounded to correspond in shape with the under or inner surface of theflange. The shaping of the root end in this manner does not involve theremoval ofany considerable portion of the outer hard wall of the root,which is thus left intact and affords a strong support for the outer endof the plug. The employment of a eylindric flange on the cap as a meansof affording lateral support to the crown when a small cylindric plug isused is also obviously inconvenient in the case of irregularly-shapedteeth, inasmuch as the fitting of the flange to such teeth requires thatsome -parts of the teeth be cut away much more than others. In the useofa conical plug with a conical cap, however, the edge of the cap orflange may be conformed to the outer wall of the tooth, and a smoothfinish thus obtained, however irregular in form the side walls of thetooth may be.

I claim as my invention- 1. An artificial tooth-crown consisting of ametal part or base adapted for attachment to the natural root and aporcelain body or veneer, said portion and body or veneer and the metalpart being provided with closely-interfitting recesses and projectionsand secured together by cement, substantially as and for the purpose setforth.

2. In combination with a natural root, an artificial tootlrcrownprovided with a plug made larger at its outer than at its inner end andinserted in and accurately fitted to a correspondingly shaped recess inthe root, said plug being made without screw-threads or similar holdingdevices and secured in the said recess by cement, substantially asdescribed.

3. An artificial tooth-crown provided with a plug, E, made larger at itsouter than at its inner en l,and stepped or shouldered, as shown, andadapted to fit a correspondingly-shaped recess in the root,substantially as and for the purpose set forth.

4-. An artificial tooth-crown provided with a plug which is made largerat its outer than at its inner end, is accurately fitted to acorrespondingly-shaped recess in the natural root, and is provided witha saucer-shaped cap or flange having its concavity on its under sidefitted on the convex top of the root, said plug being withoutscrew-threads or similar means of attachment and being seen red in saidrecess by cement, substantially as described.

5. In combination with an artificial toothcrown, a metal plug forattaching the crown to a natural root, said plug being larger at itsupper than at its lower end and stopped and shouldered, as shown, and acap fitted over the plug and root, said plug and cap being securedtogether and to the artificial crown by solder, substantially asdescribed.

6. In combination with an artificial crown, a metal plug made larger atits outer than at its inner end and a metal cap provided with a conicalflange and fitted over the top of the plug and root, said plug and capbeing secured together and to the tooth-crown by solder, substantiallyas described.

7. In combination with an artificial toothcrown, a plug for attachingsaid crown to a natural root, said plug being larger at its outer thanat its inner end and fitted to a socket in the root, and an aperturedcap covering the top of the root and the plug, said cap and plug beingsecured together and to the tooth-crown by solder, substantially asdescribed.

8. The combination, with an artificial toothcrown comprising a porcelainbody or veneer and a metal base or socket, said porcelain body and metalbase being provided with interlocking recesses and projections andsecured together by cement, of a plug made larger at its outer than atits inner end and fitted to a socket in the natural root, and a capfitted over the root and plug, said plug and cap being secured togetherand to the metal base or socket of the crown by solder, substantially asdescribed.

In testimony that I claim the foregoing as my invention I affix mysignature in presence of two witnesses.

JAMES E. LO\V.

IVitnesses:

C. CLARENCE PooLE, OLIVER E. PAGIN.

